Some of these would make an interesting stocking filler. Whilst nowhere near as Ultralight as my own http://www.theultralighthiker.com/ultralight-pen/ some of them are quite interesting. Being able to have a pen handy on your keychain is a good idea, as is the pen which expands to full size when needed;
http://www.lamy.com/eng/b2b/pico
https://www.massdrop.com/buy/tec-accessories-picopen-keychain-pen?referer=EJ89BQ
http://www.thewritingpenstore.com/c-121-wallet-and-keychain-pens.aspx
Beta Inkless Keychain Pen
Lamy Pico Pen
Pico Keychain Pen
See Also: http://www.theultralighthiker.com/waterproof-notepads/
