Spore is fun to pick up every once in a while, but it is really a fundamentally flawed game. The creature creator is really fun to play with, but the game itself is on the very weak side. It's pretty much a sample platter of different games like Civilization or Populous, but each of the game styles it takes after, it doesn't do a good enough job with - you end up wishing you were playing the game you were reminded of.
You also end up not caring about making your creature look good, but rather just attach all the parts that give your creature the stats you want, and by the latter half of the game, they want you to design so much stuff that you really stop caring completely (buildings, cars, outfits for your creatures, etc.). I really also wish there were a few more ways you could tweak your creature, you are forced to make them symmetrical, and the low complexity limit they put in is pretty annoying. It's still is fun, but for a game that was delayed by like 3+ years, you would expect a little bit more in-depth feeling of a game.