It would be remiss of me to predict a wave of desperate midlife crises in Why won't the kids leave home? without examining what exactly constitutes such a thing these days. It's generally used as a derisive term to explain frivolous and out-of-character behaviour in someone over the age of about forty.

"Introduced to popular psychology in the mid-1970s, the midlife crisis is now entering its own midlife years," says Psychology Today's Fulfillment at any age.

Sometimes a midlife crisis is triggered by an event such as illness, menopause, children leaving home, the death of a parent - or even attending a school reunion and realising that all these "old people" are, in fact, your ex-classmates. Other times they just occur with the passing of the years.

The recognition that your life is probably half over can bring on feelings of regret and a sense of lost possibilities - and result in a flurry of activity that others identify as a midlife crisis. In order to assist with the meaningful expression of your midlife crisis, I've considered ten different manifestations of this phenomenon. Some of them sound more fun than others.

Affairs: Having an affair with someone younger is a tried and tested way of compensating for your own grey hair and wrinkles. Not recommended if you're already committed but, if you're footloose and fancy free, what have you got to lose apart from your dignity?

Appearance enhancements: Shedding weight, dying your hair and using Botox are all ways of giving your outer shell a more youthful appearance than the candles on your birthday cake suggest. Is it just my imagination or do we all look far younger for our age than previous generations?

Babies: Difficult as it may be to believe, some women's midlife crises and associated lack of purpose inspire them to have a baby. There are children walking around today who were their mother's one last attempt to prove their fecundity and, ergo, their worth.

Blogging: The mantra seems to be: if you can't beat it then over-share your experience with an unspecified number of strangers. Midlife crisis blogs abound. A Google search reveals over 2.8-million.

Fast cars: Buying a sports car, preferably a convertible, is every bit as clichéd as having an affair. See TopSpeed's list of the top five midlife crisis cars which includes M-Series BMWs and Porsche 911s.

Religion: A freshly discovered sense of your own mortality and perhaps a fear of death might lead you to embrace religion in midlife. Depending on which of the world's faiths you choose, you may be promised eternal life or reincarnation. Religion cannot be beaten as an antidote to mortality.

Partying: Considering the fact they're almost guaranteed to result in hangovers and undue tiredness, late nights combined with alcohol and recreational drugs seem an unlikely way of recapturing one's youth. Nonetheless excessive partying is a well trodden path to relieving the dullness and boredom that can accompany middle-age.

Physical challenges: These can be running marathons, swimming the English Channel, climbing a mountain or taking up a new sport. You'll benefit from increased fitness levels and hopefully feel more energetic too. Unfortunately, the subtext of "I need to achieve this before old age slows me down once and for all" isn't quite so uplifting.

Self improvement: Whether it involves learning a language, going back to university or taking a Landmark Forum course, personal development is designed to make you feel good about yourself and temporarily take your mind off your creaking knees and stiff back.

Volunteering: There's nothing like helping those less fortunate than yourself to make your own middle-age angst fade into insignificance.

Have you had a midlife crisis yet - if so, how did it manifest itself? Have you watched someone's unfold? Do you plan to have one in the future?