Bangkok International Airport What to do if you have 6 hours ? - 10 Points?

Am going to Taipei by Thai air end of this month and i will be marooned inside Bangkok international airport waiting for a connecting flight heading back to Malaysia .I am sure you guys have waitied inside the airport heaps of times - For ten points tell me how to spend the time even if i have spend some dough . How expensive is the mage within the building ? Are there places to shower without blowing too much cash ?