I play a lot of my Steam games without Internet, usually because sometimes it goes out for extended periods of time.
However, there's a problem. I like to track how many hours I spend in a game, and I can't do that when Steam is offline.
I've found a way to cheat the system though. It's not a very good solution, but it works. The idea is to leave the game running for as how many hours you want to track. Of course, that's a problem due to a lot of games taking up a lot of resources, and your computer could overheat after a while, which you definitely don't want to happen while you're not at home (or not at all). So, the idea is to replace the game's .exe file with another one that won't actually launch the game, and then run the game through Steam. I used Notepad myself.
This may not work for all games, but here's my method:
1. Find a generic .exe file you'd be okay with leaving open for extended periods of time.
I used notepad.exe.
2. Find the location of the game you want to run.
Example: C:SteamsteamappscommonAlan Wake
3. Rename the game's .exe to something else.
4. Copy the generic .exe over to the game folder and rename it to the game's original .exe.
I copied notepad.exe to C:SteamsteamappscommonAlan Wake and renamed it to AlanWake.exe
5. Run the game from Steam and leave it running for as many hours as you need.
If you want to play the game again, you'll need to switch the .exe files around again, to their original names.
You do run the risk of not being able to play the game due to a mistake in naming or something like that, but that's easy to fix by checking the integrity of the game's files through Steam, which will then re-download the original .exe.
It's a bit hacky, because it's not at all automatic and things could go wrong, so use this method at your own discretion.