EDGARTOWN, Mass. (AP) _ President Clinton celebrated his 51st birthday Tuesday with an enhanced appreciation for the simple things, like good health, good times and good knees for jogging.

In contrast to the glitzy shindig thrown for Clinton's 50th last year, Tuesday's celebrations were decidedly low key. The president spent the day with his family before heading to a private fete at the Martha's Vineyard home of actor-spouses Mary Steenburgen and Ted Danson.

On the way there, several people along the road held up signs wishing Clinton a happy birthday. Among those at the party were entertainers Carly Simon and Merv Griffin and author William Styron.

``I'm very happy today. I have a lot to be thankful for,'' the president told reporters who gathered at a grove of pine trees outside the 20-acre estate where he is staying for his three-week vacation.

``I feel very blessed. I'm very fortunate to be here,'' Clinton said. ``As far as I know, I'm in good health and the country's doing well. That's the most important thing of all.''

What he was most grateful for, Clinton said, was his ``good day'' on the golf course Monday, when he is said to have scored an impressive 80, and the 2.5-mile jog he took Tuesday morning with his college-bound daughter, Chelsea, a prized moment of shared time and his first real jog since recovering from knee surgery.

``That's the longest I've been able to go since I hurt myself,'' Clinton observed.

In deference to that recovering knee, Clinton and his daughter walked and jogged at intervals on a wooded bike path, making their way around an occasional in-line skater and barely taking in the cluster of brown ducks that waddled near a pond in a pasture across the road.

Before long, round stains of sweat soaked Clinton's white T-shirt, which bore the words ``I Met Yoni Dotan'' and was a recent gift from the terminally ill son of an Israeli entertainer.

Clinton said the only thing he intended to do Tuesday was spend time with Chelsea and his wife, Hillary, ``reading and playing games and having fun with each other'' before turning himself over to more than 100 well-wishers at the Steenburgen-Danson farmhouse.

White House aides would not reveal the guest list, which likely was peppered with the celebrities and highbrows among whom the Clintons are hobnobbing while on break from Washington.

``There will probably be a face or two that are recognizable,'' said deputy White House spokesman Barry Toiv.

Such recognition was not a problem last year, when Clinton turned 50 in a front-and-center seat at Radio City Music Hall. In that celebration _ which raised $10 million for the Democratic Party _ Clinton was ribbed by Whoopi Goldberg and serenaded by some of his favorite singers, including Tony Bennett and Aretha Franklin.

This year, the only public birthday greetings Clinton got were from a throng of onlookers at the Farm Neck Golf Club and a handful of reporters he bounced past during his jog.

And while last year Clinton's birthday was trumpeted on Radio City's neon marquee, this year a lone birthday flag flew at the cottage where Clinton and the first lady are staying.

The flag, a multicolored banner with a birthday cake on it, was ``a lovely, temporary gift'' from a local family, said spokesman Toiv.

``I believe it is a family tradition, and they will need it back shortly,'' Toiv said.