I will give you a good one. Rollover, interest.
Find two brokers. One which pays interest, and one which does not.(there are plenty of these, just ask for a non-interest account- you pay $5 per day for every open position.)
Now go long GBPJPY collect 24 USD per night per lot on the interest paying broker.
Go short with same quantity GBPJPY and only pay $5 ont the non interest paying broker.
Your net is $21 positive per day per lot.
Whenever one of your accounts approaches risk levels, move money from the other account to this one.
You want more?
Regards
Yanni