What are the odds of discovering a block as a solo miner? I understand that during mining, one does not discover individual coins, but rather blocks of coins, and I heard that one block equals many coins (but how many?). I am wondering though, as a solo miner, what are the odds of discovering a new block? I guess this depends on my hardware but if we say that a GPU is 10 times faster than a CPU, and a $10 USB ASIC device is 1000 times faster than a CPU, and a $300 mining box is 5000 times faster than a CPU, perhaps one can adjust the odds estimations to reflect that. 

Also, how many BTC would I obtain if I discovered a block?
This website http://blockexplorer.com/ seems to how a variable number.
But it seems a bit like winning a lottery.
Take the total network Th/s and divide by your total Th/s. That number gives you you a number that tells you how many blocks will occur before you get one (on average).

So if there is currently 3,666 Th/s on the network, and you have a 0.55 Th/s (like you would if you have a $5,000 KNCMiner Jupiter ASIC), then 3,666/0.55 = 6,665.

That means you have 1/6,665ths of total hashing capacity.   There will be 6,665 blocks before you get one.

So if there are 144 blocks in a day, then you need to wait 46.28 days to get a block when mining solowith that hardware.  But that is assuming difficulty doesn't rise.   So what will happen with a rising difficulty is you end up waiting much longer even, and possibly never end up getting a block when solo mining.

That's why solo mining is not as profitable as using a pool for anyone without tens of Th/s nowadays.