GURPS has a few things that you can use to get started on a lighter and simplier note.
GURPS Lite. A short and free PDF that has the basic rules for GURPS.
Adventures
Caravan to Ein Arris (GURPS Fourth Edition) A free and fast to play fantasy adventure.
GURPS Dungeon Fantasy Adventure 1: Mirror of the Fire Demon
GURPS/D20 Adventure: Planet Aldo
Locations and Hot Spots
GURPS Locations: Metro of Madness
GURPS Locations: The Tower of Octavius
Resources
GURPS Resource and Play Aid page
GURPS Infinite Wolrds:IST Not a standalone product this free PDF gives you what you need to merge the GURPS Supers IST (Third Edition) setting with the GURPS Infinite Worlds (Fourth Edition) setting.
GURPS Fourth Edition Combat Cards Very nifty set of cards that list all the regular maneuvers and help you get used to combat.
GURPS Martial Arts Techniques Cheat Sheet.
GURPS Skill Categories List of skills by category to easily orgnaize things.
GURPS Magic Spell Charts A nice resource for your Magic game that shows all the Magic spells and thier prerequisites.