As I mentioned here: http://d-infinity.net/blog/derek-holland/superscience-gamma-world-and-mutant-future I believe that magic items should be a useful resource for making artifacts for Gamma World and Mutant Future. Staves, legendary items (a series of pdfs from Purple Duck) and other items that contain a lot of thematic spells and powers work well for artifacts that are following their programming. But how often is an artifact found in perfect condition?

There are a few resources for artifacts that are buggy. Personally I like the idea of a wand/rod of wonder. I don't mean using the charts for those magic items as they are, but rather writing new ones that follow the theme of the artifact but also have several significantly dangerous side effects due to poor condition. Mystic Eye Games released a 3.0 book on chaos magic, Wild Spellcraft, that has a few charts along these lines, including one that is completely generic (i.e. W% are good results, X% are okay results, Y% are bad results, and Z% are wish you were playing another game results).

I have mentioned the article on miscasting spells in Dragon 163 a few times. It could be used to develop weird primary or side effects of badly damaged artifacts.

For those who want really chaotic effects, there is the magic item charts in all the DMGs (and other sources). Just roll one or more random magic items and use those results. It would be best to do this before the session starts but those who can reskin on the fly might have fun with finding out the results along with the players.

Just think of a pen light that some how can act as a Cloak of the Bat. Does it leave any permanent side effects?