A new event for Black 2 and White 2 has been revealed on the official Pokemon site.
http://www.pokemon.co.jp/ex/atsumeyou/
If you collect stickers of all four Gen I starters (Bulbasaur, Squirtle, Charmander, Pikachu) found in certain merchandise, you can take them to participating stores to collect an Egg for your Black 2/White 2 game. The egg is one of the three main Kanto starters: Bulbasaur, Squirtle, or Charmander, and is a random distribution. It says it is possible to get multiple eggs on a single game cart (but you would have to collect another set of stickers).
The goods containing the stickers go on sale starting June 23rd, and the Egg distribution runs from September 1st to September 30th.
Each Pokemon has their normal abilities, but have special moves.
Bulbasaur: False Swipe, Block, Frenzy Plant, Weather Ball
Charmander: False Swipe, Block, Blast Burn, Acrobatics
Squirtle: False Swipe, Block, Hydro Cannon, Follow Me