"3D Fire" in 286 chars of #GLSL!
for(float i,z,d,j;i++<5e1;o+=(sin(z/3.+vec4(7,2,3,0))+1.1)/d){vec3 p=z*normalize(FC.rgb*2.-r.xyy);p.z+=5.+cos(t);p.xz*=mat2(cos(t+p.y*.5+vec4(0,33,11,0)))/max(p.y*.1+1.,.1);for(j=2.;j<15.;j/=.6)p+=cos((p.yzx-vec3(t,0,0)/.1)*j+t)/j;z+=d=.01+abs(length(p.xz)+p.y*.3-.5)/7.;}o=tanh(o/1e3);