In 1927 Professor Parnell at The University of Queensland (Australia) heated a sample of pitch and poured it into a glass funnel with a sealed stem. Three years were allowed for the pitch to settle, and in 1930 the sealed stem was cut. From that date on the pitch has slowly dripped out of the funnel - so slowly that now, 83 years later, the 9th drop is only just forming.
Interestingly, in all these years that the pitch has been dripping, no-one has ever seen the drop fall. With 3 webcams now watching the experiment 24/7, it is hoped that no-one will miss the 9th drop (when it arrives)! If you're interested in trying your luck, or at least just having a look at the experiment, you can watch the live view at http://smp.uq.edu.au/content/pitch-drop-experiment. You will probably see students of The University of Queensland milling around outside the cabinet, so it is more exciting than watching grass grow!
This 10-second time-lapse video captures the descent of the imminent 9th drop between the period of 28th April 2012 to 10th April 2013.