Something unfortunate happened to sampling in recent years. Whereas sampling used to be about creating your own instruments by recording your own sounds and editing them into something interesting, in recent years it seems as if sampling has become more about pre-made drum loops and slick, pre-packaged sample libraries. This is a shame, because today's software samplers have more sound sculpting features than ever before, and the possibilities for sound manipulation are virtually limitless. Case in point: Kontakt's various sampler modes.
Of course the standard Sampler module is there, but there are also two interesting modes called Tone Machine and Time Machine. Tone machine can be used to turn sounds with no apparent tonality into melodic instruments. Time machine, on the other hand, can be used to stretch the sound out while maintaining its tonality. Simply by adjusting settings on the Speed knob, you can really change the character of a sound into something otherworldly. Even if your software sampler doesn't offer an option like this, you can use most audio editors to do time-stretching, even if it doesn't sound exactly the same. You'd be amazed at how weird even the most mundane sound source will sound if you stretch the bejeezus out of it
The point is, with a mic and whatever is laying around, you can (and should) build completely unique sounding instruments that will really stand out from the army of presets that plague a lot of modern electronic music. Hell, you can even use one of those presets as a starting point and mangle it up until it is no longer recognizable. Just give it a try, because most modern samplists are really missing out on some of the most fun you can have sampling!
Below is an example where I took a really bad sample of my guitar and molded it into something a bit more weird simply by using Time Machine and adding some compression, chorus, and reverb. The Original sample plays first, and the Time Machine version follows.