In the past 2 years, he's been on trips with me and/or my wife to Florida, Alaska, Minnesota, and California. We've taken shorter trips to Washington, DC, Gettysburg, Philadelphia, Mount Vernon, on and on. There's a chance he'll get to go with his grandparents to Ireland and England next year. We're planning a camping vacation with my wife's sister's family (yep, they're homeschoolers, too) to the Dakotas and Yellowstone. He either does schoolwork on the trip, or he works hard to get ahead and enjoy a break from normal classwork. On all of these trips, there are educational activites and just plain all-out fun.
I'll bet those extra-curricular activities stack up pretty well with whatever the local second grade class is doing.