Grand Theft Auto Online has been thriving for nearly six years. Six years! In that time it's been home for so many communities, updates, and expansions. It's pretty insane how at any time I can boot it up, mess around, and feel like the playerbase is healthy and the game has something new: time will tell if current big hits like Fornite will withstand that test of time.
That content library is growing today with the Diamond Casino & Resort update, which adds the titular Vinewood Casino to San Andreas. You can head into the casino to just mess around, or get a penthouse and partake in extra missions beyond the general debauchery. As a note, if you have Twitch Prime you can claim a bonus "Master Penthouse," among other extras (so long as you link your Rockstar Social Club account). You can find more specific info here, but the gist is that the casino allows for poker, a bonus wheel (once per day) blackjack, roulette, slot machines, and horse racing.
Again, there's a reason I keep Grand Theft Auto V constantly updated on my PC. It pays to be able to just hop in when I want, without the headache of the massive install size on consoles to boot!