This one is also very nice:
${font sans-serif:bold:size=8}OTHER ${hr 2}
## check bitcoin price every 15 minutes:
BTC ~ ${execi 900 curl -s http://api.coindesk.com/v1/bpi/currentprice.json | python -c "import json, sys; print(json.load(sys.stdin)['bpi']['USD']['rate'])" | sed -e 's|\..*$||g' }
Checks for bitcoin price every 15 minutes 
