I really got excited this morning when I was researching a solution to a database problem.  I always find myself pouring over other peoples questions on sites like Stack Overflow until I find a solution or a clue to my error or problem.  today I was looking at a solution and discovered that the correct answer was posted using a cool online SQL site, http://sqlfiddle.com/

I know I am not always up to date on stuff, but this site is really great.  It will allow you to build a schema and test your ideas without doing any real damage to a database system.  I have always set up a test database for this purpose, but being able to quickly write a SQL statement and se what idt does all on one web page is really cool.  I can test out ideas quickly and then use the SQL code on the production database.