Old circuit boards can be found all over the place. Large boards loaded with logic chips are particularly interesting finds. Rather than let them go to waste, or trying to reuse the chips, why not turn them into a pen holder? That's what I did, and it suits my desk perfectly.
This board has 17 x 74LS chips, and 4 sram chips.. Does your pen holder have 16k of RAM?
All I did was cut the board into 4 equal sized pieces, then joined them at right angles.
For the bottom (not visible in these photos), I used a piece of mousemat which protects pen nibs.