Draw a Random Walk with Slashes
Python 2, 300 285 257 246 236 bytes


Something to kick things off. It should be possible to shrink this down further. Thanks @Maltysen for shaving 10 bytes.

from random import*
N=input()
x=y=0;G={}
exec'n=randrange(4);l=n&lt;2;u=n&amp;1;G[(x-l,y-u)]="\\/"[l^u];x-=2*l-1;y-=2*u-1;'*N
f=lambda i:range(min(x[i]for x in G),max(x[i]for x in G)+1)
for i in f(0):print"".join(G.get((i,j)," ")for j in f(1))


Generates the walk output into a dictionary G of visited (x,y) tuples, updating our location as we go. Each random step n is both either u/d (u) and l/r (l).