Roboi's Food Mart
Each city has a hidden Courier Mission which is very similar to the Pizza Delivery missions from Vice City. These are sort of hidden, however they are not too hard to find with this guide. In Los Santos you'll need to locate Roboi's Food Mart and get on the BMX. When you get on the bike you'll start the challenge and will have to speed around the map to various locations where you'll find a large floating corona. You will then need to throw a package into the corona. You do this by holding L1 or R2 to drive by, then hitting L1 or Circle. If the package goes through the corona, move onto the next one. If you miss you can drive over it to pick it back up. You will need to get through 4 levels of deliveries before your time runs out.
In Los Santos, the courier challenge can be found outside Roboi's Food Mart. This is located in Commerce which is to the South West of the Los Santos area. Look for a winding road going through a yellow-ish grassy area on the Radar. Above this to the North is a small square on the radar. The entrance to the mart is just to the North side of this square. Upon getting on the BMX you'll start the mission. You now have 6 items and must deliver to 3 of the coronas. Drive to those locations marked with a yellow blip on the radar and drive-by them to drop the package. Once they're all done, try to keep your remaining items as you'll be rewarded for them. Head back to Roboi's Food Mart where you'll start the next level and pick up more items. This time you need to deliver 4. Continue doing this and work your way through the levels. On the final level you'll need to deliver 6 items, however they are literally all over Los Santos, from one end to the other, so you need to pedal pretty fast to get there and back in time.
Level 1 - Items Held: 6 | Deliver 3 Packages Level 2 - Items Held: 6 | Deliver 4 Packages Level 3 - Items Held: 7 | Deliver 5 Packages Level 4 - Items Held: 8 | Deliver 6 Packages
Reward: Money Earned On Deliveries Roboi's Food Mart has been Acquired as an Asset.