Ideas for 40th Party

I'm throwing Jon a birthday party next weekend. I've left a lot to the last minute, I'm really bad at this sort of thing.

Does anyone have any fun ideas for a 40th party? Parties I've been to in the past have been costume parties or something like that. One party I had had a "being John Malkovich" theme but instead of Malkovich's face, it was the birthday boy. That was a good party.

Maybe the theme could simply be his birth year, although you'd have to get it together fast. Guests could come in 70's clothing, you could play music and games popular in 1972.  I think you'd be safe with anything from the early 70's, as I doubt anyone would call you out on say, a game that actually came out in 1972.

http://pop-culture.us/Annual/1972.html

http://www.popculturemadness.com/Music/Charts/1972.html

http://www.superseventies.com/1972.html

http://www.fashion-era.com/1970s.htm

It might be too much to get them to dress 70's this late in the day but you've given me the idea of getting a ton of bad 70's fake mustaches for everyone to wear.  Cheers!