The Getting Busy Bonus Pack Add-on for Crackdown has 5 achievements worth 210 gamerscore.
Complete any Stockpile mini-game in Co-op mode in fewer than 2 minutes and 30 seconds
Win every Street Race using any vehicle(s)
Win every Street Race using all available vehicles
Execute 3 flips of any type in a single jump in any vehicle
Use the Harpoon gun to attach 5 gang member corpses to a single vehicle