Here are the in-game prizes you'll be getting based on how long you've been registered:

One month or more: 5 Hyper EXP Stones that allow you to get up to a 12x EXP boost.
One year or more: A very fast anniversary mount.
Two years or more: Feel like an expert? Well now you can look the part with some anniversary fashion.
Three years or more: The mystical Purple Fox mount finally makes its debut.
In-game gifts are nice, but Perfect World Entertainment is also giving out some real world prizes to a couple lucky players. Everyone who plays Perfect World International from September 2-4 will automatically be entered to win one of two prize packs including in-game currency, a Logitech gaming keyboard and a limited edition Barbarian Tiger statue. If you want a chance at the loot, make sure you log in this weekend.

PWE will also be hosting a variety of in-game events, such as bonus EXP and powerful beginner gear for new characters. The game is also getting a couple new features: Ring Engraving to add stats to rings and a the new Phoenix Nest Wedding Chapel.