tiredQ. It's a long year and the students' motivation is flagging. What do I do?

I have an idea involving extrinsic rewards. Of course, ideally, I want my students to come bounding to class through sheer love of learning, delighted to find out what new skill they'll develop next. I want the motivation to be intrinsic. However, when that fails, it's time for crackpots! Crackpots is my word for a pretend classroom currency I print and pay to my Year 8 students in the last term or two of every year. The currency was inspired by my experiences in online games such as World of Warcraft. These games harness reward-psychology with astonishing effectiveness. Almost anything you achieve in the game wins you instant virtual cash. Using a computer drawing program, or just pens and paper, design some pretend bank notes. Print a fortune in various denominations (arbitrarily, I use the denominations of 500, 2000, 4000 and then the coveted 10,000 crackpot note). Buy an office cash-box to store the money, and get hold of an ink stamp. Give every student a folder that does not leave the classroom. When you reward students with the cold hard crackpot cash, stamp the back of the note to validate it. The students also sign their cash immediately on receipt, binding it to them alone, because they are not allowed to trade currency amongst themselves or pool crackpots together. The crackpots are stored in their folder and never leave the classroom. Get creative with your prizes. I have a list of about 30 items for sale in my crackpot shop. Examples of prizes include a merit certificate, a complimentary letter or phone call to the student's parents, a 'I'll sit where I want' card, a knighting ceremony where the student gains a title, one of my business cards, a visit from the principal, being able to write their own assembly announcement ... and so on! Bizarrely, one of my most popular items is a twig, which I simply fetch from the garden and present to the student on a platter while playing the theme from 2001, A Space Odyssey. It's all fantastic fun, and harnesses the urge to earn for learning. You can hand out money with wild generosity and abandon, like it's budget time just before an election. A class driven by reward rather than censure is a happy class indeed!