2 added 1735 characters in body
source | link

Okay, here's a much longer version (247 characters) that does full-on formatting of the output:

c,h,i,j,n,d,w[99];char s[99][99];main(r){for(scanf("%d%d",&n,&r);d=r;n=d)
h+=w[c++]=sprintf(s[c],"%d + ",n/d,r=n%d);for(;j+=w[i],i<c-1;puts(""))
for(printf("%*d\n%*s",j+(r=h-j)/2,1,j,s[i++]);--r;printf("-"));
s[i][w[i]-2]=0;printf("%*s\n",j-1,s[i]);}

Some examples of its output:

$ echo 89 150 | ./cfr
                 1
0 + ---------------------------
                   1
    1 + -----------------------
                     1
        1 + -------------------
                       1
            2 + ---------------
                         1
                5 + -----------
                           1
                    1 + -------
                             1
                        1 + ---
                             2 
$ echo 151 8919829 | ./cfr
                 1
0 + ----------------------------
                     1
    59071 + --------------------
                       1
            1 + ----------------
                         1
                2 + ------------
                           1
                    1 + --------
                             1
                        1 + ----
                             21 
$ echo 293993561 26142953 | ./cfr
               1
11 + ---------------------
                 1
     4 + -----------------
                   1
         14 + ------------
                       1
              4410 + -----
                      104 

Okay, here's a much longer version (247 characters) that does full-on formatting of the output:

c,h,i,j,n,d,w[99];char s[99][99];main(r){for(scanf("%d%d",&n,&r);d=r;n=d)
h+=w[c++]=sprintf(s[c],"%d + ",n/d,r=n%d);for(;j+=w[i],i<c-1;puts(""))
for(printf("%*d\n%*s",j+(r=h-j)/2,1,j,s[i++]);--r;printf("-"));
s[i][w[i]-2]=0;printf("%*s\n",j-1,s[i]);}

Some examples of its output:

$ echo 89 150 | ./cfr
                 1
0 + ---------------------------
                   1
    1 + -----------------------
                     1
        1 + -------------------
                       1
            2 + ---------------
                         1
                5 + -----------
                           1
                    1 + -------
                             1
                        1 + ---
                             2 
$ echo 151 8919829 | ./cfr
                 1
0 + ----------------------------
                     1
    59071 + --------------------
                       1
            1 + ----------------
                         1
                2 + ------------
                           1
                    1 + --------
                             1
                        1 + ----
                             21 
$ echo 293993561 26142953 | ./cfr
               1
11 + ---------------------
                 1
     4 + -----------------
                   1
         14 + ------------
                       1
              4410 + -----
                      104 
1
source | link

C, 119 characters

n,d,r;main(i){for(scanf("%d%d",&n,&d);r=n%d;n=d,d=r,i+=5)
printf("%*d\n%*d + ---\n",i+5,1,i,n/d);printf("%*d\n",i,n/d);}

Here are some examples of output:

$ echo 15 98 | ./cfrac
     1
0 + ---
          1
     6 + ---
               1
          1 + ---
                    1
               1 + ---
                    7
$ echo 98 15 | ./cfrac
     1
6 + ---
          1
     1 + ---
               1
          1 + ---
               7
$ echo 98 14 | ./cfrac
7

While the truncated fraction line isn't as pretty-looking as some of the examples here, I wish to point out that this was a common technique for formatting continued fractions back in the days before desktop computers were ubiquitous.