I've almost started writing a Tcl procedure to display top-10 CPU-intensive processes on a router ... and then discovered the sorted option of the show processes cpu command. Even more, starting in IOS release 12.2T, the show processes cpu history command gives you a nice CPU utilization graph. Sample printouts are included below:

router#show processes cpu sorted 1min
CPU utilization for five seconds: 1%/0%; one minute: 2%; five minutes: 2%
 PID Runtime(ms)   Invoked      uSecs   5Sec   1Min   5Min TTY Process
   5      180080      9762      18447  0.00%  1.75%  1.73%   0 Check heaps
  62         648       181       3580  0.00%  0.31%  0.12%   2 Virtual Exec
  25        4116       173      23791  0.49%  0.05%  0.00%   0 Per-minute Jobs
  30         848      1172        723  0.00%  0.01%  0.00%   0 IP Input
  81          12       357         33  0.08%  0.00%  0.00%   0 CEF Scanner
   6           8         2       4000  0.00%  0.00%  0.00%   0 Pool Manager
   4           0        86          0  0.00%  0.00%  0.00%   0 DHCPD Timer
   3           4        27        148  0.00%  0.00%  0.00%   0 CRYPTO IKMP IPC
   9           0         1          0  0.00%  0.00%  0.00%   0 AAA high-capacit
  10          52       238        218  0.00%  0.00%  0.00%   0 ARP Input
... rest deleted ...
router#show processes cpu history
                22222
    22          11111          11111
100
 90
 80
 70
 60
 50
 40
 30
 20             *****
 10             *****
   0....5....1....1....2....2....3....3....4....4....5....5....
             0    5    0    5    0    5    0    5    0    5
               CPU% per second (last 60 seconds)

    2121121112121112121 11111222222122 12211121119112121 12221
    1926405121716641818 76211100148411 70088401221831611470011
100
 90                                              *
 80                                              *
 70                                              *
 60                                              *
 50                                              *
 40                                              *
 30                               *              *
 20 **** **  ***** **** **   ****** ** ***** *   ** ***  ****
 10 ******************* **********#*** **********#****** *****
   0....5....1....1....2....2....3....3....4....4....5....5....
             0    5    0    5    0    5    0    5    0    5
               CPU% per minute (last 60 minutes)
              * = maximum CPU%   # = average CPU%
     1
    80
    60
100  *
 90 **
 80 **
 70 **
 60 **
 50 **
 40 **
 30 **
 20 **
 10 **
   0....5....1....1....2....2....3....3....4....4....5....5....
             0    5    0    5    0    5    0    5    0    5
                   CPU% per hour (last 72 hours)
                  * = maximum CPU%   # = average CPU%