Choose a bug and fix it.
Warning the bug database is not clean, there
are a lot of user questions in there that are not bugs.
Or reports against old versions where the bug
has been fixed.
If you want to volunteer to tidy this up, be my guest.
Alternatively, choose an open development task
Get involved on the mailing lists
And/Or answer questions in these forums.
If you do good work you will get CVS access.
Until then post patches. Testing other peoples
patches is another piece of work.