S.E.
Two year old birthday parties are all about cute and simple games.
I usually do homemade birthday parties by getting ideas through this website. I've seen a cute one for little girls where a few friends if girls, come dressed up to have a princess birthday party. They follow twirly music for a dance, try on "glass slippers" (shoes from your closet), decorate cupcakes, and go on a treasure hunt through various rooms of the house for the presents or cupcakes. I've done a simple meet at a shaded park and have hotdogs and potluck for other young couples and their kids. It was pretty cheap, just took a little coordination to have people bring chips or side dishes and we provided the hotdogs, water, paper products. We did a treasure hunt with clues sending the kids to the swings, then the slide, then tables, etc. until they found the birthday cake. We had a few fun games of tag with the parents, and partner tag, but very low key. We blew bubbles and chased them. Here's a website I like to get game ideas for. Good luck. I hope this helps.
http://www.coolest-kid-birthday-parties.com/