I just found this obscure reference to learning and unicycling. The authors argue that recall of prior learning can be improved by learning a new, unrelated skill.
Harvey, I. and J. V. Stone. 1996. Unicycling Helps Your French: Spontaneous Recovery of Associations by Learning Unrelated Tasks. Neural Computation 8:697-704.
"The following is a simplistic analogy, which assumes that this effect
carries over to human learning of cognitive tasks. If you have a French
examination tomorrow, but you have forgotten quite a lot of French, then
a short spell of learning some new task, such as unicycling, can be expected
to improve your performance in the French examination. Students
of French should be warned not to take this fanciful analogy too literally;
it requires the implausible assumption that French and unicycling make
use of a common subset of neuronal connections."
Mon français s'améliore...