The Collaborative International Dictionary of English v.0.48:

Avocation \Av`o*ca"tion\, n. [L. avocatio.]
   1. A calling away; a diversion. [Obs. or Archaic]
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            Impulses to duty, and powerful avocations from sin.
                                                  --South.
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   2. That which calls one away from one's regular employment or
      vocation.
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            Heaven is his vocation, and therefore he counts
            earthly employments avocations.       --Fuller.
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            By the secular cares and avocations which accompany
            marriage the clergy have been furnished with skill
            in common life.                       --Atterbury.
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   Note: In this sense the word is applied to the smaller
         affairs of life, or occasional calls which summon a
         person to leave his ordinary or principal business.
         Avocation (in the singular) for vocation is usually
         avoided by good writers.
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   3. pl. Pursuits; duties; affairs which occupy one's time;
      usual employment; vocation.
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            There are professions, among the men, no more
            favorable to these studies than the common
            avocations of women.                  --Richardson.
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            In a few hours, above thirty thousand men left his
            standard, and returned to their ordinary avocations.
                                                  --Macaulay.
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            An irregularity and instability of purpose, which
            makes them choose the wandering avocations of a
            shepherd, rather than the more fixed pursuits of
            agriculture.                          --Buckle.
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WordNet (r) 3.0 (2006):

avocation
    n 1: an auxiliary activity [syn: avocation, by-line,
         hobby, pursuit, sideline, spare-time activity]