Da hell, Spore? The first time I've been active on your servers for years and the first thing you do is download a ton of shitty adventures that I didn't even want. >.<
There is a way to control content in your Spore game, but it's convoluted and inconsistent, unless handled carefully, thanks to the way EA implemented it.
Basically, the only way to ensure you wont be waging battle against a sentient race of spacedicks is to make sure "Buddy Content Only" is -disabled- in the setting menu, then unfriend everyone and unsubscribe from every sporecast you've added, then -enable- "Buddy Content Only", and then delete everything that remains in your "Everything" folder. Otherwise, even though it's not buddy content, it was already downloaded, and will show up. Also, if you don't fully delete everything belonging to a Sporecast that you want before the next step, it won't redownload anything from it, for some reason. Also, never turn "Buddy Content Only" off again, or you'll have to do these steps all over.
Anyway, once you've purged everything in that exact order, subscribe to the Sporecasts with content you want, and add individual friends. Only those pieces of content, and Maxis creations, will show up in game. I put together a list of sporecasts and really great content-makers when manicuring content for a Spore LP, and I could probably dig for it.
EDIT: Also, if you care for it, there are a number of decent Spore Content Mods, that open up new parts, balance gameplay, etc.
Relevant Link.