If is_page() With Regular PHP
My article on WordPress' is_page() is one of the most popular articles on my site. One thing I receive questions about on a regular basis, is how to use is_page() in regular PHP.
Well the downside is, you can't. The upside is that you can still perform a similar check
Not as smooth as is_page() but still a fairly simple way to check the page you are currently on. You can easily check if it is "=="/"!=", and add in as many "&&"/"||" conditions as you want.
As always, if you have a better way to do this, or use it in something cool, let me know in the comments.