Is there any way to install apps incompatible with Android 4.1.2 (Jelly Bean) After looking around on the Google Play Store, I've found a lot of apps that 'I like the look of'. But by tapping on them, quite a lot of the time it says "This app is incompatible with your Android version." Is there any way around that?

P.S:I don't have any other Android devices and no, I haven't edited any of the files.
The Android Market pulls the OS version directly from the system.  As far as I'm aware there's no way to fake this other than building a custom ROM that fakes it, or possibly some sort of code injection.

As ce4's comment says, you'll need to obtain the app from a different device running a supported OS or through some other means (a different app store for example).