I'd like to offer up some blabber and MSPaint explanations about common pickup patterns. Here's effort 1.
-----

The pickup pattern of a mic is simply the area in which it picks up the most sound. Noises outside this area will still be picked up but with less definition and volume.

Different patterns are required for different sources. Different mics have different patterns although some are "multi-patterned" and can be switched between configurations.

If you imagine a mic to be a light source, then:

Cardioid (Cardoid?) (Car-druid?)
These pick up sound like a flashlight or torch: a cone shape. Generally this the pattern found on dynamics and some condensers. They have a small, specific area which responds well to noises and everything else is much quieter.

(Actual response and colour of mic/hair may vary)

These are used on stage for live sound - the tight pattern means increased rejection of other noise sources like floor monitors (feedback), drums and enthusiastic tambourinists.

A large amount of proximity effect is to be expected from cardioid mics - this is an increase in bass, boominess and low-mid frequency energy caused by being incredibly close to the singer's mouth.

Supercardoid
Like the above, but these shine a narrower cone. Not QUITE as narrow as a laser pen, though. There's a little area at the rear that picks up louder than at the sides, but these are very rarely problematic.

These are more suited on fixed sources, as any movement will result in a change in tone and proximity effect.

Omnidirectional
These are like overhead bulbs. Instead of shining light across the entire room, they pickup sound almost equally from all directions.

(The image was only a certain size and so the circle couldn't be made much bigger: actual pickup area may vary)

Proximity effect is harder to achieve with these mics - and you normally won't be that close to a source. Lots of room noise and ambience is picked up by these mics.

Figure of 8
I have no idea what kind of lightbulb would project this pattern, unless you had a pair of bulbs, or...
Regardless, these pick up sound well in 2 distinct areas, but with a null area toward the sides.

(With some overlap, and less floating heads)

These are used for, well...mostly as the S in an M/S setup.

My knowledge of this topic is ridiculously limited of course; please feel free to post suggestions or correct any blatant stupidity.