Facebook offers interns a lot of the same benefits the Google intern listed, but here are some benefits you only get at Facebook:

• You get to work on a social networking service people actually use
• You can choose between an iPhone and an Android phone
• Foxes on campus (and the ability to participate in endless debates over whether they’re becoming too domesticated from eating tater tots)
• Events to bring friends to like the Facebook Intern Carnival with a zip line and the Facebook Summer Party with a petting zoo
• It’s allowed to drink beer at work and date coworkers. The Facebook interns who went to see The Internship learned these aren’t allowed at Google
  Edit: a Google engineer has replied to this answer saying that the movie is wrong on both of these points. I thought at least the information in the trailer would be accurate…
• Google interns take the blame for loud parties:
  Google interns 'terrorize apartment complex with constant partying'

Things we didn’t have at Facebook:

• Heated toilet seats :(
  I think Facebook’s toilets are pretty standard
• Nap pods. It would be nice to be able to save rent (Facebook does provide housing for interns though) by living at the office but I don’t think Facebook allows it. Some people bring tents for the hackathons.
• Intern boat cruise. We went to Alcatraz on a boat but it’s probably not quite the same.