(From the Current Console Generation)
Time sinks do not have to be aimed at the casual audience or at the hardcore RPG audience. Some of the greatest series of this generation combine to create the ultimate time sinks. Vast living worlds, addictive gameplay, and thought-provoking narratives can all contribute to the "time-sinkability" of a franchise, and this generation has no shortage of time sinks for the single player.
#6 Dead Space (3 main entries)
Dead Space has a visceral nature and delves into themes of psychosis and isolation in ways that only the horror genre can. The dismemberment of Necromorphs holds up through three campaigns that will take you from a mind-shattering encounter on a desolate spaceship to an infected wasteland where you are certainly not alone. While the evolution of the franchise is not popular with everyone, the series will provide entertainment that will scratch the horror itch.
#5 BioShock (3 games)
Consisting of two of the greatest games of this generation and another solid entry with one of the best standalone DLC's, the BioShock games form one of the greatest series to begin within the last eight years. From the harsh, visceral, underwater Rapture to Columbia, the soaring city full of secrets, BioShock will introduce you to unforgettable worlds that will make you question life while realizing its true worth.
#4 Mass Effect (3 games)
The benchmark for progressive and cohesive narrative across multiple entries, Mass Effect provides a galaxy full of stories accompanied by solid, third-person shooting mechanics. Following the young Commander as he (or she) becomes a Spectre to the point where the universe's fate becomes clear, the Shepard trilogy is forever tied to this generation. With over 100 hours of content, the Mass Effect series makes for a fantastic narrative-driven time sink.
#3 Assassin's Creed
(5 games plus a portable title with another console title to be added later this year)
No time-sinkable series list would be complete without the ultimate single player franchise of the current generation. No, Assassin's Creed is not the best franchise or the most critically acclaimed, but there are just so many of them. With five console releases and Black Flag set to release later this year, you will have to plan ahead of time to play all of these games. The open-world gameplay combined with the beautiful vistas of the Middle East, Italy, and colonial America make this franchise the greatest example for creativity with fictional/alternate history.
#2 Borderlands (2 games)
The entire Borderlands series is predicated on the addictive nature of its shoot and loot gameplay. With each game providing 20+ hours of fun in a single playthrough, co-op and single player options, multiple characters to change up gameplay, and the addition of solid downloadable content, the Borderlands series will keep you entertained for hours on end.
#1 Elder Scrolls (2 games)
The greatest strength of the Elder Scrolls series comes from Bethesda's ability to create living worlds with epic quests around every corner. From saving the physical world to decorating your dream home, the Elder Scrolls will provide you the world and you just have to immerse yourself in it. Enjoy your time on Tamriel. The Elder Scrolls series is the closest video game equivalent to "Hotel California."
What did I miss? This list focused on the home console side of the gaming spectrum but are there any great current gen time sinkable series on portable consoles. Let me know.