  Recently, increasing empirical evidence indicates the extensive existence of
heavy tails in the interevent time distributions of various human behaviors.
Based on the queuing theory, the Barab\'asi model and its variations suggest
the highest-priority-first protocol a potential origin of those heavy tails.
However, some human activity patterns, also displaying the heavy-tailed
temporal statistics, could not be explained by a task-based mechanism. In this
paper, different from the mainstream, we propose an interest-based model. Both
the simulation and analysis indicate a power-law interevent time distribution
with exponent -1, which is in accordance with some empirical observations in
human-initiated systems.
