I need some recommendations for a good, but very temporary, hair color. I would in a very conservative office (civilian employee with the military), but every once in a while ManBerry mentions in passing that he likes the look of bright colors. So, one of these days I'd like to surprise him with some fun colored streaks in my hair. But, I don't know any good brands that will put pretty colors in my hair for a day or two without leaving colored flakes all over everything.

In case it makes a difference to your recommendations, my hair is (freshly) dyed dark mahogany brown. I don't care if the color shows up super vibrant, in fact he's mentioned his favorite is dark blue in black hair, I just want it to be visible.

ETA: Matthew McConaissance suggested clip in hair extensions instead, so brand recommendations would be accepted for those too. I don't necessarily need to spend the $$ on real hair, but don't want to look like I stuck a My Little Pony tail to my head.