The grail features an integrated sig rotator: quotet from the aboutubb page of the grail (note that there is a space in the ubb tags. You will have to remove it to get it working):
[ sigrotate]text1|text2[/sigrotate] - this is especially for your sig - it will choose one of the | seperated texts at random to actually include. You can use any ubb code (like [ img] within.
This is how it worked at the old forum:
They are using a sig rotator and they are probably using one written by mr.maX. He has a number of versions for different languages (PERL and PHP) and if you want to use one you should email him and ask nicely for the version you want.
Ladies and Gentlemen, there is now a different way: just hop on over to Master Suho's PHP Sig Rotator and get started right away! No messy e-mails--just you and your favorite text editor copying and pasting! And, if you order now, we'll throw in one week's worth of shock treatments, absolutely free!