Firefox (EnjiNight)

Japanese believe that all things, organic or inorganic, have spirits. Even machines have spirits. Which explains why there's anime like 'Ghost in the Shell', 'Strike Witches', 'Soul Eater', 'Hetalia' which  basically personifies inorganic things (robots, military aircraft, weapons, countries) into people.

The OS-Tan scene is the personification of computer Operating systems or software into people, especially girls. Now and then, you have people cosplaying as these OS-Tan characters.

Xbox 360-tan

Xbox 360, Playstation 3 and Wii : )

Geek Girls! (Win XP, Firefox, Windows 2000, Adobe and Win ME)

Windows 7 (Saibou-kun)

Windows XP (Ayaka)

Adobe-tan (FabiiKawaii)

Cosplay is usually about dressing up as your favorite character from a TV show, Game, Anime etc. Other than the odd guy who dresses up for laughs (tutu Halo muscle guy), there have been people who dress up as food brand mascots or food products, yummy edible things.

Ronald McSephiroth VS Colonel Strife?

That's My McMiku? : S

Wendy's Carl's Jr, Burger King, McDonalds, KFC.....?

Aqua Team Hunger Force!

Cereal Box Creature??!

Captain Crunch?!

Wonka Bar, Willy Wonka and kids!

A Tart dress?! Not bad!

Walking Onigiris?

Walking cup noodles with Naruto

Domino-Lactus?

She REALLY loves Dunkin Donuts

Optimus Pintmus!

This may be a problem if someone needs to go to the bathroom

With Carl's Jr and Jack in the Box guy

Mr California Roll

50s Diner Waitress? (KachieChanChu)

Mmm making me hungry! XD

PewDiePie, the hilarious Scary Game player/ commentator and YouTube star has quite a gained following on his YouTube channel that people have decided to COSPLAY him as well as some of the crazy enemies from the 'Amnesia' game series