Ordinance & Ordnance

With the i – a rule or law.

Without the i – military weapons and ammunition.

Stationary & Stationery

-ary – unmoving, unchanging.

-ery – paper and other writing materials, often personalized. 

"The nice stationery I was supposed to use as thank-you cards when I graduated high school sat stationary in a drawer for many years."

I'm not alone in the universe!

http://learnyourdamnhomophones.com/

Role & Roll

What can I say? Indiana Jones is a great role in a great movie. I won't apologize for coming back to him again and again on this blog. :) 

Of course, if you prefer your rolls hot and buttery, we can do that too:

Mucous & Mucus

In honor of the last four weeks of sickness around our house.
Mucous – (adj.) describing the cells and tissues that produce mucus.
Mucus – (n.) the slime produced by mucous cells and tissues. Often ending up in a tissue, come to think of it.
This one shouldn't be too hard to remember because -ous is such an obvious adjective suffix, as in "viscous," "infectious,"or, well, "obvious." So even if we can't remember the correct spelling, hopefully we can remember the part of speech we're talking about, can't we?