I've just found that Joe Albahari, co-author of the forthcoming C# 3.0 in a Nutshell, has released the Beta 2 version of his beta LINQPad - it is like Notepad for LINQ :)
There is also a challenge:
- Locate the shortcut for SQL Management Studio on your Start Menu and move it some place else.
- In its place, insert a shortcut to LINQPad.
- For the next week, perform all your ad-hoc SQL queries using only LINQPad.
At the end of the week, you will actually think in LINQ, rather than thinking in SQL and translating to LINQ. (LINQPad also allows old-fashioned SQL queries for tasks are genuinely impossible or clumsy in LINQ. You'll feel an unpleasant sense of failure, though, should you cheat and use this feature frivolously :)
If you can write all your ad-hoc queries in LINQ, you have a big head-start over everyone else in C# 3.0, LINQ and LINQ to SQL. (Further, LINQPad gives you a knowledge of LINQ that does not depend on Intellisense, and so will not fall to pieces at job interviews!) And continued use of LINQPad will keep your LINQ knowledge alive—if you're not lucky enough to be using LINQ in your current projects.