For 2008, the IRS permits you to contribute up to $15,500 in tax-deferred money

to the Thrift Savings Plan (TSP). 

If you will be age 50 or older during 2008 and you have made -- or will make

-- the maximum amount of tax-deferred contributions for the year ($15,500), you

may also contribute up to $5,000 in additional "catch-up" contributions.