I saw this somewhere else and figured that I could recreate it!!

So Hubby and I went for a little trip to 'the Depot' to collect our supplies.
* 1 roll of that rubbery shelf liner stuff in a neutral color(about $3-$4).
* 1-2 bags of river rocks from the garden center (the 1 to 3 inch variety was about $3 a bag)
* 1 tube of Landscaper's adhesive - I bet you could use silicone, but hubby was with and he's all about making things STRONG. (about $3)
* 1 can of polyurethane
First, I poured out all the rock on the back patio and rinsed them off and let them dry for a day.
Second, I took a roll of that rubber shelf liner stuff and cut it to the size that I wanted.
Third, I started scavenging through all the rocks to find ones that fit together in a cool pattern. It took a while, but I got them all situated. We bought two bags just so that we could find all the 'perfect' rocks.
Fourth, I laid down wax paper underneath the mat, WHICH I DO NOT SUGGEST DOING!, so that the adhesive wouldn't stick to the floor. NEXT TIME, I would use something more durable or easily tearable, not sure what at this point.
EDIT: Someone here suggested using polyurethane plastic sheeting, the cheap drop cloth kinds because nothing sticks to that!!Fifth, I started glueing the rocks down to the mat using the adhesive in a caulk gun. I ended up changing my design a little just because I couldn't keep it all in order as I transfered the rocks from the floor to the mat.
EDIT: Also someone suggested using outdoor silicone because the landscape adhesive is really meant to stick rocks together, not really for rocks to plastic. I can say that it's been a while since I originally posted this and about 4 rocks have fallen off my mat, but it's also been moved in and out many times because of the hurricanes and moving to a new house. Sixth, I waited for two days before I started messing with it. I cut the waxed paper off the back and it was a real pain. I had to cut around ever dot of adhesive because I couldn't peel the paper off the adhesive. BUT...live and learn right?!
Like I mentioned earlier...use the plastic sheeting to avoid this head ache.Seventh, I trimmed the extra rubber backing off the edges so that it looked cleaner.
Eight...to be completed... I am planning on putting glossy polyurethane on the top to seal it too!
Hope you like it. Comments appreciated!!