After an impromptu iMessage from a hacking bud (poojinky), just as I was closing up burp for the day after an epic web app test; my day was made a bit more amusing. There may be more, but there is at least one amusing hidden 'feature' in Burp that will give you a chuckle. So, I'll get straight to it...
1. Start up Burp and point the browser you're using it with to any site.
2. Right-click the target IP or URL in 'Target > Site Map' and select 'Simulate manual testing' (my favourite feature I must say, after Intruder).
3. With the manual testing simulator open, click on the window to focus on it.
4. Type 'burp' (without the ''s).
Props to Dafydd for being a funny guy.
(I would take screenshots for the less familiar, but it would give it away!)