I worked with a California real estate developer who sets up an entity owned by his inherited, self-directed Roth IRA as the recipient of the gains on his deals. This structure allows him to avoid all federal taxation on his deals and withdraw the money and spend it at any time. He made about $400,000,000 on a land deal in 2006 that all went into his inherited Roth IRA. He bought himself a $32M beachfront home in Laguna Beach not long after the $400M came in. Easier to do if you just avoided $80M in capital gains.

And no, it wasn't Bill Gross, and I will not reveal his name.