The Timer feature allows you to set a date in the future and have the block display a countdown timer. The Timer is stylesheet aware, so you can have the text be any size, style, font and color, and you can put a relevant background picture or color behind it. You can elect to display any or all of the time components--seconds, minutes, hours, days, months, years--though obviously some make more sense than others.
The Opinion Poll CBA allows you dynamically and simply create opinion polls for your site. Simply enter your poll question, then enter possible responses, one per line in the Responses field. Runnng tallies are displayed after a user submits a response.
The Enhanced Clock allows you to turn parts of the
time/date display on and off so as to allow for labels that would
advance with the clock. It's pretty easy to envision uses for an app
that allows you to stick a month date or year into a block to give the
page a dynamic feel. Should be stylesheet aware.