We are finished with the English book and are watching the movie "Megamind" as a time killer.  I made a crossword for the following day.  There are a few difficult words, so we will play hangman and I'll teach the new words before handing out the crossword.  This activity was made for 6th graders, but you might be able to get away with 4th or 5th if their level is high enough.

You can also go to www.megamind.com, which has tons of activities and games.