I have never really attended a child's birthday party before (except when I was a kid but it was different back then). What are you supposed to do at birthday parties?

When LO turned one a few of my friends (with same age babies, we had the same due date so our kids are a few days apart) hosted a join party, basically just a get-together and we exchanged gifts. I didn't go to their individual parties and I didn't specifically throw a party for LO.

2nd birthday is coming (end of January, YIKES!), and I am toying with the idea of doing a party. I am not crazy about renting a venue because he's still young! It is also quite cold to be outside also. So if we were to do a party at home, what do people do for toddler birthday parties??

Any suggestions for activities that you have seen / done and loved? Ideas needed