I started lifting weights over three weeks ago (as of writing this) because I want to bolster my physical strength and sculpt a better body.
Simply put, Russian Bear 5000 is an excellent lean weight-gain product. Drinking these shakes after doing some hefty weight-lifting sessions has helped drastically improve my physical strength in a relatively short period of time. This has helped me to be able to go from leg pressing 85 pounds to 130 pounds in three weeks among other strength-training exercises (keep in mind that physically, I'm pretty small).
There's two flavors available, chocolate and vanilla, and while I like both, the chocolate flavor is my favorite. You can mix the powder either with water or milk, but I mix mine with milk so that it's creamier and I get more calcium (so I develop stronger bones to go along with the stronger, bigger muscles).
The "normal" serving size is to mix five full scoops with a whole gallon of milk, but this is only for the mega body-builders. For smaller people, you can just mix a full scoop with a regular amount of water or milk you'd drink in a glass.
If you plan on getting this stuff, I strongly suggest you get a Blender bottle to go with it.