Here's a list of all content that has been posted in the ropebox:
Alex No's Super Mario 2D Land (Full Hack)
Silver Scarlet's Touhou Ports (Music) – Video
Oh Hell No's The Senate (Full Hack; Unreleased) – Video
JackTheSpades' Sprite GFX Routine Creator (GUI Tool)
Silver Scarlet's Touhou Mario: Imperishable Night (Full Hack)
AxemJinx's Rise to the Challenge Rearranged Soundtrack (Music)
WhiteYoshiEgg's Message Box Expansion (Patch) – Video
Golden Yoshi's Hack 2 (Full Hack)
S.C.O.R.P.I.O.N./metalgearhunter's Devious Four Chronicles (Full Hack; Demo; Screenshots; Videos)
THY's Blue Flamingo (Demo)
Purple Rex's Lunar Legends (Demo)
Undy's Choconilla Rise (Demo) – Video
andy_k_250's Super Mario Bros. - The Wicked Star Story (Full Hack; Unreleased; Screenshots)
spel werdz rite's Palette Editor (GUI Tool)
Arctic Avenger's Charge of Corruption (Demo; Music)
Meltfire's Super Mario 64 - Year of the Plumber (Demo) – Video
HyperMario's Stuff Thread (WIP Hack; GFX)
Daizo Dee Von's Hallway of Treasure (3 Full Hacks; GFX)
Eevee's Sicari (Demo)
Masterlink's 2013 Music releases (Music)
Kipernal's Sprite Remapper (GUI Tool)
Koopster's Vanilla Twist (Demo; Vanilla)
WhiteYoshiEgg's New Hack (Demo; Unreleased) – Video
Egadd's Dark Side of the Kingdom (Collab; Demo)
Sokobansolver's Mario Must Die 2 (Kaizo, Demo) – Video
Archie's Kaizo Island (Kaizo; Yoshi's Island) – Video 1; Video 2
J.U.M.P. Collab (Full Hack; Unreleased; Collab; Talkhaus) – Video
Deeke's Æther (GFX)
Carld923's C3 Stuff (GFX; Demo)
MaxodeX's Ports (Music)
By the way, I am also featuring Youtube videos that show off these C3 threads. Post your videos here and I'm likely to feature it as well.