Are you looking for a way to waste the day? Then shame on you! You unproductive scum give the human race a bad name! Get back to work!
…are they gone? Good. Fellow procrastinators! I present to you the Pokémon Tower Defense flash game! But this diversion does not merely haphazardly place those adorable pocket monsters in a standard game of tower defense; it brings over many of the series' well-loved conventions. For example, you can capture weakened Pokémon during any level, who you can then use in your fight against the coming horde. Each Pokémon can also level up and learn new moves.
Yes, it is as much fun as it sounds. You can check out the game at MoFunZone.