By Dan Weil Yes, the rate was great, but there were some serious restrictions. People are rushing into I bonds so fast that the only place you can buy them, the government’s TreasuryDirect web site, crashed. The reason why investors are flocking to the site is that Oct. 28 is the last day that those buying I bonds, which are U.S. savings bonds, can get a 9.62% interest rate. The rate is expected to drop to 6.47% Nov. 1. It’s actually a little silly to sprint for the higher rate. The maximum amount of bonds you can buy is $10,000, and the 9.62% interest rate will last for only six months. It ge…