Then there are a few possibilities.
1> Part of your file structure is corrupted. Go to Steam and tell it "Verify Integrity of Game Files", it's one of the options. You don't need to fully reinstall the game or anything, this'll find any flawed files automatically. This is the most likely cause of any crash.
2> You've edited some of the core files yourself to avoid learning how to make an actual mod and/or because you want to use the changes in multiplayer. Bad idea. It can be fixed just like #1, since the game will see any files that don't match its baseline as "corrupted", and will undo your changes.
3> Your game isn't fully patched after all. It's surprising how many people forget that they turned off the auto-patching and then complain that mods don't work...
4> While this shouldn't NEED to be said, apparently it has to: if you pirated the cracked version of Civ5, then it doesn't matter how well-patched you are, most mods won't work at all.
5> You're using mods that are just not up-to-date. Without telling us which mods they are, we have no way to gauge this. If by "ones from this month" you mean the ones on the front page then yes, they should be fine, but if you just mean that you downloaded them this month, then that's no guarantee they work. But most mods, even if they're horribly outdated, won't cause an actual crash unless they never worked in the first place, so this one's not very likely.
Now, if none of those help, the next step is to enable logging and check the logfiles at the time of the crash. To turn on logging, to into your config.ini file; it'll be in your user directory, which on Windows 7 is My Documents/My Games/Sid Meier's Civilization V/. About 2/3rds of the way down will be "LoggingEnabled = 0" or something similar; turn it on (1), and do the same for some of the other logging options in the same section if you want.
The next time you run, the game will place logs in your Logs/ directory (off of the directory your config.ini is in). The ones you generally want to check are Database.log, xml.log, and Lua.log. Each of these has a small number of errors from the vanilla game and DLCs, so look at what they produce sans mods to get an idea of what's safe to ignore. Then, try turning on the mods and starting a game; when it crashes, see if any of those logs recorded something unusual.