As Scott posted on the blog, you can use your IRA to invest in TechShop and get tax free gains. I have had Roth IRA with a traditional brokerage (Vanguard in my case) and decided to split out some of those funds to invest in TechShop through a self-directed IRA. It was amazingly easy to do.

1) Decide whether you want to invest in something other than mutual funds, stocks and bonds. With a self-directed IRA, you can buy rental property and make unsecured loans (subject to limitations to prevent double-dipping) at places like www.prosper.com, and invest in business start-ups.
2) I called my bank, USAA, and told them I wanted to open a self-directed IRA. The whole process to about 5 minutes, over the phone. When I hung up, I had a Roth IRA money market account just waiting for funds.
3) I called my broker and said I wanted to sell $$ worth of sharers in order to transfer cash to another Roth IRA account. That took about 10 minutes
4) Have the current custodian transfer funds from one account to the other.
5) Wait for the funds to clear the minimum 7-day holding period.
6) Write a check or wire funds to Techshop's account.
7) Build something- I need to make some bunk beds for my kids
8) Profit - unlike a traditional investment in stocks, this means that the annual profit distribution gets paid back to your self-directed IRA instead of watching a stock price go up.

Now, if your bank does not know what a self-directed IRA is and your brokerage doesn't either, don't be surprised. But http://www.theentrustgroup.com/locations/franchises/62/ can help you set-up a self-directed IRA.

I'll be happy to answer any questions that I can, but I'm not licensed to give investment advice.