Are you working on a desktop software?
jamesbritt: My company, Happy Camper Studios, has just released JotBot: http://www.getjotbot.comIt a cross-platform desktop-based time-tracking application.We used  JRuby + Swing plus Monkeybars.     It needs a license key to run; we have a Web service handling that to generate 30-day trial keys or fully-registered non-expiring keys.  That's handled by Ramaze on Glassfish.Sales are done through Shopify and Google Checkout.