Some house rules we use in our Victorian GURPS campaign.
The way we do character creation is a little different than the by-the-book rules.
We play with a fifth "sense" attribute per the optional rule in the Compendium I. As described in the rules, the IQ attribute is a composite of mental acumen, problem-solving ability, natural aptitude, willpower, and sensory perceptions. We have divorced sensory perceptions from IQ and give everyone an addition 10 points to start with that can be used to raise the sense attribute with accute vision, alertnes, etc. should they so desire.
It was brought up that people should be able to raise their Sense attribute in the same way that people can raise their IQ attribute post-generation, so we allow people to raise Sense at 5 points per level (just like Alertness) up to their IQ attribute (assuming Sense is lower than IQ, of course).
(If we were playing at a higher tech-level where the IQ attribute is even more important, we might even divorce "will" from the composite and play with a seperate "will" attribute (for a total of six attributes) and 120 point characters.)
We've written up a page entitled Aquiring Advantages After Character Generation which spells out the officially allowed ones, some speculative ones, and some "temporary" advantages that a character might aquire.
We also allow the following advantages to be purchased after generation: one level of Strong Will, one level of Charisma, Literacy, and Fit. A character can also buy Very Fit if he got Fit at generation.
We're investigating letting allowing Very Fit to be purchased by even
those who didn't buy Fit at generation, and possibly Rapier Wit.
Rotating GM
Lotsa folks play with just a single person assigned to play the GM while everyone else plays characters. We play a little differently in that we have a "rotating GM" policy: anyone can play the GM if they want to but it typically requires that you A) know the rules pretty well, B) have an adventure written up, and C) Find someone to babysit your kids (if you have them). (We look forward to the day when our kids are old enough to join us in gaming sessions.)