Are you ready?
As I write this, it is now almost 45 mins since the mainnet was synced and reached block 499407 and mining was enabled on the Bitcoin Gold blockchain.
What is it?
Bitcoin Gold is a PoW (Proof-of-Work) altcoin which utilizes the Equihash algorithm. That means it's easily mineable with both nVidia and AMD GPUs! Though to be fair, nVidia based GPUs (especially the current "Pascal" series) tend to produce the best (read: most-efficient solutions/watt) results.
Why the delay?
Bitcoin Gold was the result of a hardfork of BTC that happened back in late October. The blockchain was supposed to be ready for mining shortly thereafter, but due to some additional tweaks needed in the code (namely, Replay Protection), it was delayed until now.
Get in on the action!
You can get started by visiting the main website http://bitcoingold.org and selecting a pool. Each pool has specific instructions on where to get the correct software, and how to configure it.
Good luck and happy mining!