Basic metric conversions game -- no frills, but it provides immediate feedback. Check out the other activity; there is a print out worksheet for students to complete afterward.
More than two dozen integer games, ranging from ordering on a number line to comparing integers during a "space race." There also are worksheets galore for using integers with all four operations.
Site has worksheets with 10 levels and increasing complexity from one variable/one step/no exponents to up to three variables and five steps (and everything in between).