I love hunting down bundles of digital comics. It's a great way to (legally!) pick up a lot of cool stuff and even find a lot of newt things without busting my budget. It also occurs to me that I've been doing a poor job of sharing that love, so I'm going to change that.
First, a note about my preferences: I hate proprietary formats with a fury that is generally reserved for stepping in dog poo. You won't find me sharing the latest bundles from Comixology because my opinion is that they only rent comics. That said, it's just my opinion and an awesome deal is still an awesome deal, so share 'em if you got 'em.
Because I avoid proprietary stuff, a lot of the bundles I run across are from independent publishers (I've never, EVER seen a Marvel or DC bundle that is open-format). Dynamite does a lot of bundles, as does IDW, Boom! Studios, and less often Image. A lot of the output from those publishers is licensed, so there's often something I really love in there that makes it worth the cost all by itself and the rest is almost a bonus. Even in mixed bags there is usually something am willing to try out. Bundles are a super-cheap way to expose yourself to good comics you might otherwise not bother with or even know about. In my experience I've found a lot more gems than duds.
I am assuming here that pretty much everyone is familiar with CBZ format and torrenting (most of these offer or require the ability to download via torrent), but if you have any questions just ask.
HumbleBundle frequently does comic bundles and has a Dynamite Comics bundle up right now. Kind of a random assortment of things, but a few good ones in there and the price is right to try some new stuff. This bundle goes until Wednesday. Of those I've only read Shadow v1 (good Shadow story, but only middling Ennis writing), and Legenderry (I'm not much for steampunk, but it's an amusing mash-up).
[Not comics, but Humble Bundle also has a bundle of SF ebooks--almost entirely Asimov, Bester, Zelazny, and some early Wild Cards. They'll be adding more to it next Wed when it hits the second week.]
Groupees also has a dirt-cheap bundle of a bunch of indy stuff I haven't heard of. Really though, for $3 it's worth it even if only ONE of those is any good. Big drawback is that a bunch of it is pdf-only. Apparently some of the publishers literally don't even know what CBZ format IS, which is... I don't even know how that's possible.
And I guess this BitTorrent bundle from Dynamite Comics is still up (it's been up for something like two years now, which is highly unusual). 30 comics for free, over a hundred more for only $6. They don't offer CBZ either, but epub is almost literally the same thing; just change the file extension and you're good to go. some of the stuff in here nicely compliments the Dynamite HumbleBundle above.
Any others? Please share them!