How to Bring Your Face to a Sword Fight

Parrying Unarmed Attacks GURPS Basic Set Campaigns p.  376 says:

Parrying Unarmed Attacks: If you successfully parry an unarmed attack (bite, punch, etc.) with a weapon, you may injure your attacker. Immediately roll against your skill with the weapon you used to parry. This roll is at -4 if your attacker used Judo or Karate. If you succeed, your parry struck the attacker’s limb squarely. He gets no defense roll against this! Roll damage normally. 

This rule has some problems. It's actually pretty vague about what kind of damage you do ("normal damage", duh) and it can result in some silly outcomes and degenerate tactics.

A Possibly Nonsense But Playable Solution to The Crossbow Conundrum

So there's a problem with crossbows in GURPS. I go into it here. Essentially Rated ST has no limits, and nor does it change bow stats no matter how arbitrarily high it gets. This is despite the TL4 Steel Crossbows saying they exceed this nonexistent limit at the cost of halving ST for range and damage (which pretty clearly makes them useless).

Nonsentient Allies

 The GURPS Ally (p. B36) advantage expressly allows nonsentient (IQ 0) allies (and even specifies that they have no cap on point cost relative to the PC; p. B37), and GURPS allows (more-or-less) for almost anything to be built as a "character". However, many GURPS GMs seem to find this to be pretty abusable and don't allow or use this option.

Santa Claus and Signature Gear

Sgt. Clause gave himself a shave waver for Christmas.

Signature Gear is an advantage in GURPS that gives you a piece of equipment that's part of your character's concept and gives it "plot protection"; if you lose it (without deliberately getting rid of it) you will get an opportunity to get it back. Ideally this should work for characters who aren't wealthy but have some iconic bits of gear worth more then they could afford, but sometimes there are problems with the pricing.

Patthfinder Wounds and Vigor House Rules

In my "backwards" Iron Gods campaign I decided to use the "Wounds and Vigor" system instead of hit points (which have always bothered me a little). In play we have found a couple of holes in those rules and I've had to make some rulings.