How quick is quick?
Here are four levels of quick, you can chose one depending on your schedule, your desired purse and your willingness to comit crime.
1) Gamble. There are several small-time tables you can play at any casino, some of which require little amounts of skill to earn some pocket money. These are usually poker variants. You take a small amount of time to learn both sides of the game - what you control and what the dealer can (or can't) control. Sure, lcuk is still part of it, but with some common sense and sensibility, you can regularly come out with a few bills more than when you came in. I have friends who do this regularly. This creates income within a week and requires a small investment.
2) Sell drugs. Start small, build up your clientel based on loser bottom feeders or first-timers who can be easily cheated, don't get noticed, and when you have enough money, pull out and disappear. The disappearing part is easiest if you're not into drugs at all, so when you vanish, there is hardly any way people can contact you. Unfortunately, I do know people who have done this, and it isn't the most honest way of getting a quick buck, but if you need to make some money, this is a pretty fast way to do it. And hell, if you become interrested, there's always possibilities of moving up and earning more money. This takes several weeks and requires a moderate investment, but can easily earn money in the thousands.
3) Bartend. Take a local course for a couple hundred bucks, show serious interest in the bar/restaurant industry, have the time of your life in the classes, meet new friends, socialize, learn the ins and outs of working the racks, and soon enough you'll be certified and experienced to work. After you've completed your courses, talk to your instructer, who probably owns his own joint, if not definitely knows people in the business. He/she may know someone who has an opening somewhere. You'll probably get thrown on the floor bussing tables at first, but again, show interrest and soon enough you'll be getting bartending shifts on quieter nights. Keep at it and before you know it, it will only have been a few months after you've finished your bartending courses and you're working the hot shift making $500+ a night. This plan is my favorite of the set. Instead of spending money on your Friday nights, you'll be earning money instead, and hell, people buy you drinks anyways. I know kids buying new cars with bartending money alone. Pretty good for a 22 year old student. There was a write-up in the paper recently of a girl waiting on a table when it was F1 season here. She earned a $3,000 tip on one table. Pretty killer. This plan takes a couple of months, but it is honest, amazingly fun, and makes excellent money.
4) Penny stocks. This is pretty straight forward. Take an afternoon to read a ... for Dummies book on stock investing, gather a few hundred dollars and go online. Parents like this route, so you can actually come up with a lending plan with them to start you up. Buy some penny stocks and who knows, maybe you'll be looking at a few hundred percent gain on some lame-o mining-exploration company somewhere. Again, I know people who've made considerable money on penny stocks. This is the most long-term of the lot, but is definitely not that long in the investing world, takes several hundred dollars to get you going, but the payoffs are pretty good if you pick them right.
There you go. The drug-selling one is probably the weakest of the bunch because of obvious reasons, but it does pay - there's no arguing that. The bartending one is something I am personnaly in the midst of and is by far the funnest.