If you touch the CLOCK pin with your finger, and the
clock pin should not be connected to anything else,
and if you are within 1 meter or so of the AC mains,
via a any wiring or appliance. You should get the
display to count @ 50/60 Hz. Your body should act
as an antenna and pick up a small amount of the mains
induced voltage which will/should be enough to drive the
clock input.
You will also see this effect if you touch the probe
lead on a CRO ( oscilloscope )
EDIT
NOTE: The 4026 is a CMOS device and can be damaged
by ESD ( Electrostatic Discharge ) so if you have been
zooming around on a carpeted floor, make sure you
discharge yourself first before touching any ICs, chips etc. (any appliance with a metal case and pluged into a
wall socket should be Earth or Grounded, even when OFF)