Add three sendings-off, for Zat Knight, Ricardo Carvalho and Ashley Cole and this was a Boxing Day thriller in the traditional sense.
Shaun Maloney hit a brace before Andriy Shevchenko scored from the penalty spot just before half-time.
Seconds after the restart and he hit his second before Alex shot the Londoners into the lead.
Villa fought back to level through Martin Lauren, before Chelsea seemed to nick all three points with two minutes to go as Michael Ballack arrowed in a free-kick.
But in the dying seconds Cole handled on the line from Gabriel Agbonlahor and Barry dispatched the ball with ease to secure a point.
Villa fully deserved to go into the lead on 14 minutes when the visitors struck from a fine Maloney volley from ten yards out, after John Carew headed on Agbonlahor's defence-splitting pass.
Agbonlahor could have lashed in number two on 20 minutes but his angled right-footed blaster just went high of Petr Cech's goal from eight yards out.
Frank Lampard, desperate for his 100th goal for the Blues lasted just 26 minutes being replaced by Ballack.
Chelsea was roused from their slumber to have their first effort on target a minute later through a shot from Claudio Pizarro, but Scott Carson held the ball well.
The home side had a fair claim for a penalty on 28 minutes when Ashley Cole appeared to be bundled over inside the Villa area by Olof Mellberg, but referee Phil Dowd ignored the appeals.
Agbonlahor forced Cech into a brilliant save on 35 minutes when his low drive from ten yards out was smartly by the giant keeper.
Joe Cole almost levelled the scores on 38 minutes when a rare, incisive attack by the home side saw the England midfielder come in from the right and let fly with a strong left-footer, but the ball went straight into Carson's midriff.
Then one minutes from half-time and the unthinkable a Cech error and Chelsea lost goal number two.
Maloney, wide on the left, sprinted past Pizarro and the cut inside to the edge of the Chelsea area before letting fly with a fine right-footer which Cech just let bounce off his body and into the net.
But deep into injury time and Chelsea got a penalty when Knight tripped Ballack and was red-carded for the foul.
Up stepped Shevchenko to send Carson the wrong way and put the ball into the keeper's left-hand corner.
Villa manager Martin O'Neill replaced goalscorer Maloney with defender Curtis Davies at the interval.
But it took Chelsea just four minutes to get level with a wonderful right-footed strike from just outside the penalty area by Shevchenko, which zipped past a hapless Carson
Ballack tried a long-range effort of his own on 57 minutes, but this time Carson was equal to it.
Chelsea's comeback was complete on 66 minutes when centre-back Alex pushed forward from defence and, after smart interchange play with Shevchenko, the Brazilian let fly with a rasping low right-footer which arrowed past Carson's despairing dive.
But Chelsea's fragility in defence allowed Villa to get level when Martin Laursen beat the offside trap from an Ashley Young free-kick and volleyed home with a cool right-footer past Cech from six yards out with 18 minutes remaining.
Team numbers were evened up on 80 minutes when Ricardo Carvalho needlessly put in a double-footed challenge on Agbonlahor and was shown a straight red card by Dowd.
Then came Ballack's 88th minute blaster of a free-kick to put the Blues back in front, before Chelsea committed football suicide when Cole handled Agbonlahor's header and Barry slotted home to give the visitors a deserved point.