Here's a pretty problem, which I heard of recently from Scrabble player Eric Harshbarger (who heard it from another player, Jeff Myers, who says the problem has been kicking around for a few years): arrange the set of 100 Scrabble titles to make four 5x5 double word squares with all 40 words taken from one of the standard Scrabble word lists such as the Official Scrabble Player's Dictionary.
"Double Word Squares From Scrabble Tiles,"
Word Ways: Vol. 39
, Article 10.
Available at: http://digitalcommons.butler.edu/wordways/vol39/iss2/10