If you have young kids, you could try Sesame Place, in Langhorne near Philly. Six Flags America's Hurricane Harbor in Upper Marlboro is the area's other 800-pound waterpark gorilla. As for rafting, the Upper Youghiogheny (http://gorptravel.away.com/gorptravel/rafting-guide/maryland/upper-youghiogheny-river.html) or Lower Youghiogheny (http://gorptravel.away.com/gorptravel/rafting-guide/pennsylvania/lower-middle-youghiogheny-river.html) are both excellent rafting rivers just on the outer edge of your three-hour radius. Lastly, Delaware Water Gap NRA (http://vacation.away.com/pennsylvania/travel-v2-cid358223-delaware-water-gap-national-recreation-area-cid350266-active-and-adventure-vacations.html) offers some good canoeing; it's about 3.5 hours north of B'More.