BUILDING VOCABULARY
John's Word Search Puzzles
WORDLand
Dictionary and glossary list
Thesaurus.com
Root words
OED Online a day complete with pronunciation, spellings, etymology, quotations and date chart.
Vocabulary University
A.Word.A.Day subscribe for a daily adventure
Building a better vocabulary
Merriam-Webster's Vocabulary Builder
SuperKids Vocabulary Builders
Vocabulary help page