I've recently been messing with the Remind language grammar, and I would welcome some comments and test files, especially from people who are use some of the more obscure features. Here is the file:
http://skiadas.dcostanet.net/uploads/Remind.tmLanguage
Atm there is not support for multiline commands (i.e. a command continuing in a separate line). I hope to add it soon.
Haris