Interactive
Quia

Quia: Awesome Antonyms Match Up

For Students 2nd - 5th Standards
Match up pairs of antonyms using a concentration, simple matching or flashcard approach. Site claims that over 90 pairs are used, so multiple plays are possible.
Interactive
New York Times

New York Times: Crossword Puzzle: Musical Instruments

For Teachers 9th - 10th
An interactive and printable crossword puzzle developed by the New York Times Learning Network. The theme of this puzzle is Musical Instruments.