Display - for a program or runtime environment (whatever suits the style of your language) - the top ten most frequently occurring functions (or also identifiers or tokens, if preferred).

This is a static analysis: The question is not how often each function is
actually executed at runtime, but how often it is used by the programmer.

Besides its practical usefulness, the intent of this task is to show how to do self-inspection within the language.

bagOfCalls := Bag new.
Smalltalk allClassesDo:[:cls |
    cls instAndClassMethodsDo:[:mthd |
        bagOfCalls addAll:mthd messagesSent 
    ].
].
(bagOfCalls sortedCounts to:10) do:[:assoc |
    Stdout printCR: e'method {assoc value} is called {assoc key} times.'
].