Location: The nerd's old house.
Reward: $25
Nerds rule, jocks drool. You must defend the Nerd's lair from the onslaught of the jocks. The mission, comprised of three different stages, is dependent on the amount of jocks you kill: if any of the jocks breaks through your defenses, you will fail the mission.
Defend the Gates
Nothing special, nothing difficult. Meet the jocks by (a) fighting where the jocks are running from, or (b) shooting from the hills. Defend the Gates is the exception to the rule: if a jock breaks through the gates, you won't fail the mission, but you'll move to the next segment, the Spud Cannon.
Spud Cannon
Now, if any of the jocks make it through your defenses, you will fail. Luckily, the cannon has unlimited ammo and is auto-fire. Find the path where the jocks are running from, and incessantly shoot at that point.