Birthday Party For And 11 Year Old In Spring Time

I am having a birthday party for my 11 year old and looking for something to do fun and break in the spring weather so being that i have to seed my lawn every year due to heavy traffic as i have 4 kids and do day care so my idea is to have an easter egg hunt for the kids and then a scavenger hunt for the birthday girl to find her gifts so please if you have any other ideas i am open to any other ideas you may have