Do you have a theme? My son is having a unicorn party for his 3rd and we are planning on doing things to go with the theme like making unicorn horns to wear, decorating ice cream cone horns to eat, throwing rings onto "horns" (traffic cones), etc.
For his 2nd, we made I spy bags, pencil zippered bags filled with beans, rice and fun things to find- mini animals, buttons, etc. we also ran the bubble machine for them to chase them.
I try to have at least 1 craft, then 2-3 games and free play mixed in. Marshmallow or balloon toss is good for this age, obstacle courses, chase, etc
Jul, Mama to 1/2 dozen boys; and been doing those "off-beat" parenting things way before they were cool and learning more each day!