Common items & harder riddles | Encyclopedia Harry Potter OP Guide

1. Incendio on every torch/lamp (of course except these which are already lightened ;), Incendio on every gargoyle, Incendio on every stove.
2. In some places you'll find small items which give you points as you look at them (by pressing Enter). Such items are: chains (Boathouse), roof tiles (Paved Courtyard, you have to climb up to the roof, use the gutters), book (Viaduct Entrance), statue (Defence Against the Dark Arts), painting (Defence Against the Dark Arts, move the bookshelf in order to uncover it), blackboard (Defence Against the Dark Arts, make sure that you've looked at both sides!), plant (Herbology), jar with gillyweed (Herbology), chests (Gryffindor Boys' Dormitory, there are few of them), one of stones (Stone Circle), chest (Umbridge's Office, you have to open it up with a spell first).
3. Boathouse: right next to the building you will find six birds, three on each side. Birds on the right side will fly away when you approach them. On the left side you'll find a basket full of fish. Cast Wingardium Leviosa on it in order to lift a fish and then pass it to one of the birds, then the second one and last one.
4. Entrance Courtyard: in each corner of the courtyard you will find Hogwarts Insignias covered with leaves. Take a broom (which lies nearby), cast Wingardium Leviosa on it and sweep up leaves in order to uncover all Insignias. Symbols of each house will show up over Insignias and under benches on courtyard. Move benches (use Wingardium Leviosa again) over the Insignias. The house symbols have to match.
5. Transfiguration Courtyard: start from using Wingardium Leviosa on the big globe in the middle of the courtyard. House symbols will show up. Move benches the exact same way as in the previous riddle, so the symbols match. You'll end up with a lot of points and four Insignias more.
6. Paved Courtyard: this riddle is similar to previous two. Climb up the stairs to the upper part of courtyard (if they're broken, use Reparo) and fix four sculptures to bring on the Hogwarts Insignias. Cast - as always - Wingardium Leviosa on benches and match the symbols.
7. Viaduct: walk through entire viaduct. The place you're looking for is near the big door leading to the Viaduct Entrance, under one of the torches. Climb up the wall there. Points are yours.
8. Herbology: in one of rooms you're going to find four square flowerpots, a bucket and a watering can. Cast Wingardium Leviosa on the bucket and hold it for a few seconds over each pot to fill them with earth and then do the same thing with watering can.
9. Clock Tower Courtyard: there's a pear tree in the courtyard. Collect fruits lying under the tree and put them in a basket (Wingardium Leviosa). Use the same spell to pick some straight from the tree (and put them also into the basket).
10. Gryffindor Common Room: use Wingardium Leviosa to move the table under the painting of a wizard flying on a broom (near the fireplace). Talk to this painting, and then to the painting of a sleeping wizard (another side of the room). Now cast Accio on one of the books on shelf near chess players. Then move the table back to the center of the room and catch the snitch (you need to Enter in the right moment; the better idea is to press the button repeatedly all the time, after a while the snitch should be yours).
11. Defence Against the Dark Arts: at the end of the stairs in tower you'll find a mop. Throw it to the bottom of the tower - there are two puddles waiting to be cleaned up.
12. Defence Against the Dark Arts: in the classroom of DAtDA open up all the desks by casting Wingardium Leviosa, then stand in front of the first of them and cast Depulso to cause some kind of domino effect.
13. Myrtle's Bathroom: open every single door in bathroom (Depulso) and then close the ones closest to Myrtle.
14. Suspended Bridge: repair the gutter next to the bridge (Reparo) and climb up. That's all.
15. Trophy Room: dust two trophies with a duster (Wingardium Leviosa) and then take a closer look at them.
16. Hospital Wing: make all the beds (Depulso), move the screens (Accio) and light the stove.
17. The Owlery: near the tower entrance there's a blind alley where you'll find a sack of mice. Feed three nearby birds with mice (Wingardium Leviosa).
18. Great Hall: you can cast Wingardium Leviosa on a few of tables in the hall.
19. Hagrid's Hut: raise one of pumpkins from Hagrid's garden using Wingardium Leviosa and put it on chimney of his hut.
20. Stone Circle: two of all stones in the circle can be moved using Wingardium Leviosa, one of them is in the shape of sphere while the other one is a cuboid. Move "the other one" near other (the closest) stone and then climb up onto it.
21. Prefects' Bathroom: open one of the doors with Depulso (press C to check which one pulses). The weird egg will show up. Move it in the big bath and cast Accio on bath.

The riddles which include Hogwarts Insignia are all similar.

Movies, pictures and other stuff are another reward for collecting Discovery Points. You can check them out in the Reward Room. Next movies are unlocked after collecting 70, 230, 400, 590, 800, 1040, 1320, 1630, 2000, 2420, 2930, 3540 and 4360 points. (By the way, there's nothing interesting in the last one. :)

There are also many other ways to gain some points...