strange ranking activity

So, every night around 7pm, my website home page gets knocked completely off Google. Around 9am the next morning, it returns again.

This has been happening every day for the past 7 days or so. After 7pm, not even "site:mywebsite.com" brings up my index.html page. The next morning, everything is back to normal.

I suspect Google is testing it's latest algoroithm update, but has anyone else experienced this?

not experienced it myself, but I would love to have your problem. I get phone calls every fucking night - at all hours.

I've actually noticed this for one of my websites. Every night, anywhere between 7 and 10 EST, according to SB, my site is no longer ranking for two keywords that I'm tracking. The next day, it's back where it was +/- 3 spots. This has been going on for the past week and a half.