Relative to other bonds US treasuries are a lot less attractive today.
http://www.investopedia.com/university/bonds/bonds3.asp
http://data.cnbc.com/quotes/US10Y
But the price is not that simple. Since bonds are paid periodically, the market price factors in the next coupon. Would you buy a bond at the same price 1 day before paying coupon than the day after? Of course not! So market price is called "dirty" because it has the next coupon implicitly considered. There are different ways to make it a "clean" price, depends on the country.
I bought a few with cash on hand in the retirement and college savings accounts.
From Google Finance:
Bonds [yields]
3 Month 0.42% +0.02 (5.00%)
6 Month 0.53% +0.03 (6.00%)
2 Year 0.90% +0.07 (8.43%)
5 Year 1.48% +0.12 (8.82%)
10 Year 2.07% +0.12 (6.15%)
30 Year 2.86% +0.10 (3.62%)The bond market is extraordinarily efficient at pricing risk, and right now, they're beginning to price a significant risk of a long-term US default.