18th birthday party ideas?

What are good things to do in the winter? Something for a group of 6-10 people.

Something that young people aged about 18 would love, something that'll keep you warm in the cold of winter, something that's not expensive, something that doesn't require a high level of fitness but is still a fun and sometimes energetic physical activity, something that will bring you all closer together and take friendships to the next level, something that will make you all feel good - releasing endorphins and adrenaline, something which will involve you all shouting out each others names in excitement... hmm.....

How about bowling?! 

Pictionary is always fun.

Scavenger hunt--can be indoors, outdoors or both. Truth or Dare--indoors. Golf--outdoor obviously. I know guys who golf on new years day regardless of the weather. Skiing Wine tasting Video game tournament playing an old school Atari game. Start the party with games you would have played at your 8 yo birthday party. Move onto more adult activities. A 24 hour party starting at the time the birthday boy/girl was born. Plan an activity every one to two hours. Go out to eat.

Go explore abandoned buildings.

Go sky diving.

I seem to be noticing a tread in your posts involving alcohol. Like the grog a little, do ya, Kay?