With DJ-Suggester you can achieve that and much more.
DJ-Suggester is a new extension that provides abilty to suggest article or DJ-Catalog2 product (more supported extensions coming soon).
The idea is simple. Once you enable the plugin you can select if it should suggest articles from any category or from the category the user is in, same when it comes to DJ-Catalog2 products (it also suggests another product from the same or different category - depending on your settings).
What's more DJ-Suggester allows you also to put any module inside the slide-in box. This can be any module!
Check the short video presentation: