[J/M Combo of the day] Golem Replication

It's actually several million. Let's walk through the process. (If math makes your brain hurt, I suggest you skip ahead to the next question now!) The first step is easy. One Precursor Golem sees a spell that targets only a single Golem, so it radiates the spell onto the other two Golems. This creates 10 new vanilla Golems from resolving Rites, 5 new Precursor Golems from resolving Rites, and 10 new vanilla Golems from the 5 new Precursor Golems' enter-the-battlefield ability. So now we have 6 Precursor Golems and 22 vanilla Golems.

The second Rite is where things get ugly. The Rite triggers the spell-copying ability of six Precursor Golems, and each of those abilities resolves separately. When the first ability resolves, it creates a bunch of copies of Rite of Replication. Those copies go on the stack above the remaining spell-copying abilities, so they will resolve and create a boatload of new Precursor Golems and vanilla Golems. Those new Golems will be taken into account by the second spell-copying ability, which will create kicked Rites of Replication for all Golems on the battlefield at that time, and they will spawn even more Golems to be seen by the third spell-copying ability, and so on and so on. In the end, you get the result of six generations of exponential growth, which yields an absurdly large number of Golems.

I'll spare you the detailed calculations, but the result depends on whether you target a Precursor Golem or a vanilla Golem. That's because the original target only gets the original Rite of Replication targeting it, whereas all other Golems get several copied Rites targeting them. You'll end up with 233286 Precursor Golems and 3359242 vanilla Golems if you target a Precursor Golems, while targeting a vanilla Golem yields a total of 279936 Precursor Golems and 3779142 vanilla Golems. In any case, it should be enough to win the game provided that you can use those Golems for something awesome before your opponent finds a Lightning Bolt!