Favorite tricks with linux kernel boot parameters?
Solution 1:
In Debian (and probably Debian-derivatives like Ubuntu) the options are documented on the man-page initramfs-tools(8).
Solution 2:
The old standby for when you really break something in your init system is to add init=/bin/bash to get taken straight to a shell. Great for fixing root passwords!
Also sometimes it's nice to change the output verbosity of the kernel. Adding "quiet" or "debug" can take this a couple directions.