I've only been there a couple of times and it didn't seem very busy, but I'm sure there are leagues that play there. The only other bowling alley I know of close by is on base.
Did a Google search and found this:
MF Clinton Lanes
7610 Old Branch Rd.
Clinton, MD
Phone: 301-868-6660
AMF Waldorf Lanes
11920 Acton Lane
Waldorf, MD
Phone: 301-843-1494
Esperanza Bowling Lanes
BLDG. 22654
Rt. 235
Lexington Park, MD
Phone: 301-863-2695
Lord Calvert Bowl
Near Merging of Highway 2/4
Huntingtown, MD
Phone: 410-535-3560
St. Charles Bowl
109 Post Office Rd.
Waldorf, MD
Phone: 301-645-4770 or 301-843-2244