Here's my first mod, an altered XCOM1 ruleset. There's many small changes, and this should be compatible with other ruleset mods, as this replaces the default xcom1rulest.rul, in the ruleset folder.
I'd advise you backup your default xcom1ruleset.rul with a copy. Just replace your xcom1ruleset.rul with this one.
Here's some of the changes:
Tank/Cannon fires explosives, instead of AP
Heavy Laser Tweaked
Floaters have a minimal psionic ability (can cause panic)
Stun Bombs have 4 shots
Laser Tank Tweaked, and improved
And a number of other small changes.