Not "Cool", but poker related:
This is a tattoo of a generic poker chip that you buy in Walmart. "A day to learn, a lifetime to master, and a couple of months to figure out that you have a piece of shit chip that's worth $.25 on your arm."
Use of chip denominations to show birth date or other significant date. Like tattooing money on your body with denominations like $12, $4, and $85.
Again, non standard denoms. $10 and $20 chips are very uncommon.