Alice in Wonderland is a great theme for a birthday party, especially if you won't be hosting the party on your child's birthday!
Two years ago, Big Sister requested an UnBirthday party in March, since we'd been on vacation in Florida for her birthday in February. It was fun to make cupcakes for this party, instead of a big cake! There are so many things you can do with this theme: the white rabbit, the cheshire cat, the playing cards, bread and butterflies, flowers, etc.
For activities, we had a craft table garden, where the kids could play with plasticine and create paint-with-water pictures from Alice in Wonderland. I made the giant flower and mushrooms out of bristol board. It's hard to see in the photo, but there are "bread and butterflies" and "rocking horseflies" on the wall, too!
We also played "Pin the Watch on the White Rabbit" and "Alice Says" (like Simon Says). Between that and the food, the kids were content just to play together, and we didn't feel like we needed any other scheduled activities for a 2 hour party. We didn't have any prizes for games. Each child got to bring home a notebook and pencil as a party favour.
...and of course, we sang the UnBirthday song instead of Happy Birthday!