What you are looking for is a tailored employee reward / incentive program, rewards could be anything really, from cash, either through target bonuses or raises, to schedule flexibility, cool new toys and promotional items.
Personally I enjoy getting first choice on projects, and a bit more flexibility when it comes to working hours and vacation time but you will have to tailor the program to your team and company culture. It's a bit trial and error, there isn't a one fits all solution and it will fail horribly if you don't have solid performance metrics. If after a while you see that you only reward the same couple of people, just promote them already, and continue the program for the rest of the team.
If you are looking for non monetary awards, you should take a look at this excellent article, from which I think the more feasible rewards for a small company are:
Flex those hours. If there's one free reward that rises above the rest, it's flexible work schedules. Nearly every expert we contacted suggested flex time as a perk that offers the most gain with the least pain.
Give them a free pass. Levine suggests giving out a certain number of free days off to employees to use as they see fit.
Let them phone it in. Telecommuting programs can relieve stress and make workers feel more appreciated, as well as more productive.
Remember the secret words. “The two most underused words in corporate America that get the highest ROI (return on investment) and ROT (return on your time) are the simple words 'thank you,'” noted Michael Guld, president of the Guld Resource Group author of "The Million Dollar Media Rep: How to Become a Television and Radio Sales Superstar ."
But you should read the whole of the article, there's some good advice in there.