Sandra Bullock Ryan Reynolds

Cue the latest round of Sandra Bullock and Ryan Reynolds dating rumors. The movie stars are on vacation together in Wyoming ... RIGHT NOW!
Yup, Sandra and Ryan have definitely hooked up ... for a hike, along with Sandy's adorable adopted son Louis Bardo, and some other friends.
Still, Ryan carried Louis in a backpack during a nature walk!

Can't you just FEEL the chemistry there?

Bullock and Reynolds were first linked last year after their respective splits from Jesse James and Scarlett Johansson, but there was nothing romantic.
The trio is vacationing in Jackson Hole, and while we know they're good friends, Ryan recently broke up with Charlize Theron, and she's single, so ...