[GoIllini]

T-Bond futures are traded on the Chicago Mercantile Exchange, one of the largest financial exchanges in the world, and the largest in the US. They're issued by and guaranteed by the federal government, so I don't think they're a scam.

There's several ETFs that invest in these guys. A cursory search on yahoo finance should give you an idea of the market.

I don't recommend T-Bonds right now. Locking into a 3.5% yield for the the next 30 years doesn't make a lot of sense when inflation's running at 4% (11% measured the pre-1983 way). The last time that inflation was essentially 11%, the fed raised rates to the double digits. A rate hike will mean that the current value of T-Bonds will go down, and allow you to buy T-Bonds on much more favorable terms.