Mortgage interest rates are in freefall, having dropped five of the last seven weeks. They're now at the lowest levels in their half-century history, according to Yahoo Finance. For people looking to buy a home or refinance, this is great news. However, you'll have to get in line.

Twice in the last week, I've had friends in Linn County refinance their home mortgage, to the tune of big savings. One went from just under 4% to 2.5% on a 15-year mortgage. Her monthly payment is dropping by $200. Another went from 3.75 percent on a 30-year loan to 2.5 percent on a 15-year loan. He shared with me that 30-year rates were between 2.75 and 2.875 percent in the Cedar Rapids area when he was loan shopping last week. That's crazy. That's the lowest in history.

Just how crazy is it for lenders? Matt Weaver of Cross Country Mortgage told CNBC,

It’s absolute pandemonium. The industry right now is certainly inundated with requests. Let’s put it this way, we are like Home Depot during a hurricane.

Will mortgage rates continue to fall? I wouldn't wait. There's big money to be saved right now and they've already reached 50-year lows. Gambling with that seems silly to me. Buy or refinance now but be prepared to wait. Lenders are very, very busy.