I am constantly forgetting what the special little codes are for formatting .NET strings. Either through ToString() or using String.Format(). Alignment, padding, month vs. minute (month is uppercase M?), abbreviation vs. full word, etc. I can never remember.
I have the same problem with regexes, but luckily there's Expresso to help me out. It's awesome.
Is there a tool like Expresso for experimenting with formatted strings on standard types like DateTime and float and so on?