Is anyone else having an ad screen pop up while reading my blog?

I do sometimes, randomly, and if I let it count down it comes back to here, but if I click on the link to skip the ad, it takes me to the advertised web site. I'm not sure what this is, if it's something Google's doing or what. I'm using Chrome as my browser. I haven't noticed it on any other website, including other Blogger blogs. I don't know how to stop it, either. But if you are having it pop up, let me know in the comments, and that way I'll know it's not just me. Weird. And if it is happening to you, I'm very sorry. I decided a long time ago not to put ads on this site, and I'd like to keep it that way.