No, recently google has not announced any updates. But i am seeing some of my website's page rank has changed now since last night.

Google releases updates almost every day. Just because they don't announce anything doesn't mean nothing's happening.

It is true, changes in Google happens everyday, either a competitor is doing well and you're not. You should try to build a site that is based from the fundamentals of high quality content and SEO...with your strong foundation, your site can in some ways be Google proof.

yes, on 21th nov, panda has been updated and also ready for another update.
Confirmed: Google Panda Refresh #22 On November 21st; 0.8% Of Queries Impacted

There is no update by google yet. If you want to get informed about google's update then simply follow matt cutts on twitter or you can visit searchengineland.com to find latest updates by google.

Don't worry about google updates too much.

1. just push your urls up the same way a LEGIT url got to google page one.
a. it shows up on a blog
b. somebody else blogs it.
c. somebody shares it on facebook.
d. a big blogger blogs it.
e. it shows up in Reddit
f. 23 small bloggers reblog.

follow this pattern and you're set. it's gotta look organic.

if you make it look like a bunch of dudes in India are on the job... sorry. =)

Why we expect a bad impact of Google updates in most case we get benefit if we are genuinely working.